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Ozone is a highly reactive molecule that easily reduces to the more stable oxygen form with the assistance of a catalyst. Cl and Br atoms destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, [18] a chlorine atom reacts with an ozone molecule (O
During the 1970s, research indicated that man-made chlorofluorocarbons (CFCs) reduce and convert ozone molecules in the atmosphere. [4] CFCs are stable molecules composed of carbon, fluorine, and chlorine that were used prominently in products such as refrigerators. The threats associated with reduced ozone pushed the issue to the forefront of ...
Because the concentration of CFCs in atmosphere is very low, the probability of a terminating reaction is exceedingly low, meaning each radical can decompose many thousands of molecules of ozone. Even though the use of CFCs has been banned in many countries, CFCs can stay in the atmosphere for 50 to 500 years. This causes many chlorine radicals ...
Scientists spent years campaigning for a ban on the ozone-damaging chemical CFC-11, but 30 years after it was phased out in the 1987 Montreal Protocol, someone somewhere is breaking the rules.
The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for example, has an ODP of 0.05. CFC 11, or R-11 has the maximum potential amongst chlorocarbons because of the ...
The non-selective nature of the oxidation means the ozone has to be well controlled if a specific outcome is required. This can be done by maximizing exposure of the molecules, compounds, proteins, and cells to the ozone that need to be reacted with or destroyed while minimizing exposure to non-targets.
Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon (CFC). It is a colorless, faintly ethereal, and sweetish-smelling liquid that boils around room temperature. [5] CFC-11 is a Class 1 ozone-depleting substance which damages Earth's protective stratospheric ozone layer. [6]
A recent report from the United Nations included some dire news about the fight against climate change. It said current pledges from countries to curb emission will probably not stop global ...